Android platform based terminal devices (e.g., smart phones, tablet computers, etc.) become increasingly popular along with rapid development of intelligent terminal devices. Android is a Linux platform-based open-source handset operating system, and the Android platform is composed of an operating system, a middleware, a user interface and applications, where an underlying layer of the platform is based upon a Linux kernel developed in the C language and serves only fundamental functions, a middle layer of the platform includes a function library and a virtual machine, and an upper layer of the platform includes various applications.
At present, an Android platform based terminal device is connected to a Personal Computer (PC) through a Universal Serial Bus (USB) connection line, and then a data transmission scheme as adopted is typically either the Media Transfer Protocol (MTP) or USB Mass Storage (UMS), and these two data transmission schemes of MTP and UMS are used or present alone.
After the Android platform based terminal device is connected to the PC through the USB connection line, it transmits and shares data with the PC in the following two implementation schemes: in one of the implementation schemes, the MTP file transmission technology is adopted alone to enable the PC to share both an internal storage of the terminal device (a storage partitioned using a File Allocation Table (FAT) or a storage partitioned using the Fourth Extended File System (Ext4)) and an external storage (e.g., a Secure Digital Memory Card (simply an SD card)) (typically FAT-partitioned) or to share either the internal storage or the external SD card memory; and in the other implementation scheme, the UMS scheme is adopted alone for data transmission to enable the PC to share both the FAT-partitioned internal storage of the terminal device and the external SD card memory or to share either the FAT-partitioned internal storage of the terminal device or the external SD card memory.
In the scheme of transmitting and sharing data with use of the MTP file transmission technology alone, the terminal device allocates, as much as possible, the internal storage to the Android system for use, but due to the limitation of the file transfer protocol of the MTP itself, transmission and sharing of data between the PC and the terminal device through the USB connection is limited to transmission of only a file, and the PC can not control in real-time the contents of the internal storage of the terminal device, for example, the PC can not modify the file.
In the scheme of transmitting and sharing data with use of the UMS mode alone, both the internal storage in the terminal device and the external SD card memory share data with the PC in the UMS mode, but due to that the terminal device allocates a part of a storage space in the internal storage as an FAT partition while establishing the USB connection with the PC, and this part of partition can not be used to run an upper application of the terminal device, the size of the standard Ext4 partition, in the internal storage of the terminal device, available to the system may be lowered to some extent.